The present invention relates to a link coupling used in a reformer for beverage or other container bottoms and, in particular, to a link coupling using a stepped pin.
In certain metal container fabrication processes, including those used for producing aluminum beverage containers, strength, durability and/or resistance to damage of the container can be enhanced by providing predetermined shapes or profiles of the can bottom portion. Certain shaping procedures involve use of a reforming apparatus which employs a pivoting rigid link for positioning and/or controlling motion of a reforming roller. In previous approaches, a substantially cylindrical pin is used for coupling the rigid link to other components of the reformer. The pivot connection(s) between the link and other components is susceptible to wear. The rapidity with which wear occurs accordingly affects the frequency at which the pins and/or associated bushings and the like, must be replaced. Replacement of these parts typically requires shutting down a production line with disadvantageous economic consequences. In some cases maintenance is performed substantially off line, often including replacing the rams. Accordingly, it would be useful to provide a configuration and method for reforming which can reduce wear on the reformer link assembly (or components thereof) and/or otherwise reduce the frequency at which production lines must be shut down for reformer maintenance or repair.
Furthermore, as reformer components wear, there may be deterioration in the precision with which the roller is positioned and thus departure of the container bottom shape from the intended shape or position. Such departures can reduce the container""s strength, durability or resistance to damage. Accordingly, it would be useful to provide a reformer configuration and method which can reduce and/or delay wear-induced departures of container bottom shapes from intended shapes.
Once it is determined that a reformer should be repaired or maintained, the magnitude of the economic disadvantage flowing from the shut-down of a production line is related to the amount of time required to perform the repair or maintenance. Accordingly, it would be useful to provide an apparatus and method in which repair or maintenance of a reformer, and particularly of pins and/or bushings used in a reformer link assembly, can be performed relatively rapidly (e.g. compared with previous apparatus and methods) preferably in a substantially standardized fashion.
The present invention includes a recognition of the existence, nature and/or source of certain problems of previous approaches and devices, including as described herein. According to one aspect, the present invention involves the use of a link pin which has a stepped, rather than a cylindrical, profile. Preferably, the stepped pin is used in conjunction with a flanged bushing. Without wishing to be bound by any theory, it is believed that increased lifetimes and reduced wear achieved using embodiments of the present invention are at least partially attributable to the reduction or elimination of axial gaps or spacings which commonly occurred between components in previous configurations or approaches.
In at least some embodiments, increases in lifetimes and/or reductions in frequency of maintenance or repair involves the use of high-wear-resistant bushings for contacting the link pins, including ceramic bushings.
In one aspect, movement of rollers used for reforming an inner wall of a metal container bottom such as an aluminum beverage container is controlled at least partially using a rigid link coupled to other components of a reformer apparatus by a pin having a stepped profile. The stepped-profile pin preferably defines first and second shoulder regions. Undesired spaces or gaps in the pin-axial or thrust direction are reduced or eliminated by closely-positioning bushing flanges or thrust washers adjacent the shoulders.